python多進程為什麼一定要name="main"？

01-07

python多進程為什麼一定要__name__="__main__"？
如果一個函數使用了多進程，供其他函數調用，要怎麼寫？

python多進程沒有必需__name__="__main__"。

但

windows 平台有特殊要求

Since Windows has no fork, the multiprocessing module starts a new Python process and imports the calling module. If Process() gets called upon import, then this sets off an infinite succession of new processes (or until your machine runs out of resources). This is the reason for hiding calls to Process() inside

if __name__ == "__main__"

since statements inside this if-statement will not get called upon import.

請看

這樣理解python中的if __name__ == "__main__" - 通過python學會編程 - 知乎專欄

小任務寫成函數，再用Process(target=函數名, args=(函數的參數,))

from multiprocessing import Process import os


def info(title):

    print title

    print "module name:", __name__

    if hasattr(os, "getppid"):  # only available on Unix

        print "parent process:", os.getppid()

    print "process id:", os.getpid()
def f(name):

    info("function f")

    print "hello", name

if __name__ == "__main__": info("main line") p = Process(target=f, args=("bob",)) p.start() p.join()